An electric vehicle, also referred to as an electric drive vehicle, is a moving vehicle using one or more electric motors as driving system. Unlike petroleum-based transportations which are moved by the energy from gasoline, the electric vehicles use electric power as their propulsion. They won't generate waste gas. Noise is also less. A motor is a common equipment to drive an electric vehicle. Due to long time use, the motor needs a huge capacity battery module as a power source. It is better that the battery module is rechargeable.
According to Taiwan E-Scooter (ETS) association and its relevant provisions of the specification from Electronics Testing Center (ETC), Automotive Research & Testing Center (ARTC) and Industrial Technology Research Institute (ITRI) in Taiwan, when a charger is charging a rechargeable battery module of an electric vehicle, the driving motor should cut off from its power source. For the sake of safety, a power cutting-off circuit should be designed in case of hard acceleration of the motor. However, general chargers have no such power management design. Output ports of the chargers are only positive and negative terminals. It is simply designed for charging. At most, there is a communication interface existing in between. Such structures can not meet the requirements mentioned above.
Review of the priors, there are some invention which provide innovative ways to fulfill the requirements. Please refer to FIG. 1. U.S. Pat. No. 8,143,843. The patent disclosed that an electrically-driven hybrid vehicle includes a charging circuit having a charger which is connected to a high-voltage battery and a charge-time connection switch. The switch is connected between the high-voltage battery and the charger, a charger ECU, and a battery ECU. The battery ECU is activated when a voltage signal is inputted, and when determining that the state of the high-voltage battery satisfies a chargeable condition, connects the charge-time connection switch, activates the charger ECU and transmits a signal representing the battery state to the charger ECU. This invention has a good way to monitor and fine tune charging status of the battery ECU. However, it can not decide to stop providing power to a motor when the charger ECU works.
Another related prior is shown in FIG. 2. RO.C. Patent No. 365,142 discloses an electric motor vehicle. It comprises a control terminal, an AC-DC converter module, a battery and a motor. The control terminal can be excited to generate a cut-off signal. The AC-DC converter module has an AC-DC converter and a relay. The AC-DC converter is electrically connected with the battery of the high voltage power supply to the battery and converted to at least one low-voltage power supply, such as 3 volts, 5 volts, or 12 volts for electrical components (for example: headlights, brake lights, headlights, horn, etc.), or electronic components (for example: relay control terminal, etc.) in the electric cars. The relay is electrically connected with the control terminal, the AC-DC converter, the battery and the motor, respectively, to receive the low voltage power from the AC-DC converter, so that the its loops can execute normally switching power conduction. When it is electrically conducted in the loops, high voltage power supply from the battery can be transmitted to the motor via the relay circuit. Therefore, the motor operate. When the relay receives the cut-off signal from the control terminals, the relay can switch its loops to be electronically cut off, so that high voltage power supply from the battery can not be transmitted through the relay circuit to the motor. Thus, the motor stops.
The relay and the AC-DC converter electrically connected to each other. Therefore, the relay can receive the lower voltage from the AC-DC converter, rather than high voltage. The invention has advantages in generating less heat and save power consumption. It is pity that the present invention can not apply to control power for motor when the battery is charged.
According to the explanation above, a charging system of an electric vehicle allowing the motor of the electric vehicle to stop running when the battery module is under charging is still desired.